Bio-Based Surfactant-Mediated Interfacial Regulation of a Dual-Responsive Nanopesticide to Enhance Foliar Deposition...

Biological surface barriers and uncontrolled agrochemical loss severely limit the efficiency and biosafety of conventional fungicide delivery systems. The development of nanopesticides (NPs) with excellent controlled release and foliar deposition properties offers promise for overcoming the low efficacy and environmental risks. Herein, azoxystrobin (AZOX) was loaded onto zeolitic imidazolate framework-8 (ZIF-8) and encapsulated with pectin to construct AZOX NPs, followed by incorporation of lauryl betaine (BS-12) to develop AZOX NPs with BS-12. The formulation exhibited pH- and pectinase-responsive characteristics, enabling microenvironment-responsive fungicide delivery. BS-12-mediated interfacial engineering significantly reduced surface tension and improved wettability, thereby enhancing deposition and retention on leaf surfaces. The formulation exhibited a median effective concentration of 0.263 mg/L, demonstrating in vitro antifungal activity against Rhizoctonia solani that was 4.7 and 6.6 times higher than that of AZOX NPs and AZOX suspension concentrate, respectively, and an in vivo efficacy of 83.81% against rice sheath blight. Furthermore, it enabled bidirectional transport in rice plants and improved biosafety. This study goes beyond conventional formulation strategies by integrating dual-responsive release with interfacial regulation, addressing both inefficient pesticide delivery and pesticide loss caused by insufficient foliar retention.